1. Field of the Invention
The present invention relates to an automatic seat belt system, and particularly to an automatic seat belt system in which, by a simple operation, a webbing restrains an occupant or releases the occupant therefrom.
2. Description of the Related Art
A slider is provided in such a manner that it can be moved from a webbing-releasing position to a webbing-restraining position along a guide rail. One end of a webbing is supported with to the slider. In addition, the slider is coupled to a flexible tape as an elongated member or an electric motor through a wire. When the motor is energized, the slider moves along the guide rail. The tape manifests a lost motion piece, which is fixed to the motor side, extending from the slider to the motor, and which is used to place the webbing to either a webbing-restrained state or a webbing-released state.
There is disposed in the webbing-restraining position, a slider holding member, i.e., a shoulder anchor which is fixedly secured to a vehicle in order to hold the slider in the webbing-restraining position. The shoulder anchor has a pawl rockingly moved by the lost motion piece which is brought into contact therewith. The pawl is urged by a spring in the direction of a path along which the slider travels.
When the occupant sits in a vehicle seat and the door is closed, the motor is energized to displace the tape in the longitudinal direction of the guide rail. When the slider is moved in response to such a displacement so as to reach a location near the webbing-restraining position, the pawl is pressed by the lost motion piece so as to be expelled from the traveling path of the slider.
When the lost motion piece is further moved into the webbing-restraining position, the pawl is released from being pressed by the lost motion piece. Thus, the pawl is turned by the urging force of a spring so as to be held in engagement with the slider, thereby holding the slider by the slider holding member, i.e., providing the webbing-restrained state.
When it is desired to release the webbing from being restrained to the occupant, the motor is reversed so as to move the tape in the direction opposite to the direction referred to above. Thereafter, the pawl is pressed by the lost motion piece against the urging force of the spring, so that the pawl is released from engagement with the slider. Under this condition, the slider is caused to move toward the front of the vehicle, thereby releasing the webbing from the restrained occupant.
In the conventional system, a pawl is necessary for engaging the slider so as to hold the slider in the webbing-restraining position as described above.
Thus, when it is desired to move the slider from the webbing-restraining position to the webbing-releasing position, it is necessary to release the slider from being engaged with the pawl before the slider is moved. Therefore, the conventional system has the problem that the slider cannot be immediately moved when the webbing is released from the occupant.
When the slider is moved from the webbing-releasing position to the webbing-restraining position, it is necessary to expel the pawl from the traveling path of the slider by using the lost motion piece before the slider is moved so as to be brought into engagement with the pawl. Thus, the conventional system has the problem that the slider cannot be immediately engaged with the pawl upon restraining the occupant by the webbing.